From a wrapper of the above-mentioned type (U.S. Pat. No. 3,508,699), it is already known to provide compensation for tolerance variations by providing locking tabs having two lateral projections so that the two bottom panels can be joined together in two different relative positions whereby either one or the other lateral projection will engage with the edge of the locking aperture. However, even this step does not suffice for substantial enlargement of the permissible range of tolerance, because the two projections on each lateral edge of the locking tab have to be relatively close to each other. Otherwise the forward projections of the locking tab would prevent penetration into the locking aperture if the dimensions of the articles to be packaged are at the lower limit of tolerance, because in that case the entry of the forward portion of the locking tab is hindered by the lateral projections.